SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9296886349a036686a85bf7acdfa4501322d8c5bb8e92f97dcc6b9a9af38c0f6' 
  AND token = '3hJwzVNAK1e09t835EEXmPuCnjhF8cQwwdZBLv+AmN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}